The objectives of this proposal fall into two sequential parts. First, to determine the feasibility of employing a low-fat (20% of total calories) diet to reduce recurrence rates and increase disease-free survival in Stage II (axillary lymph node positive) breast cancer. Over a 10-month period the study will assess: a) acceptance of the diet in patients receiving adjuvant chemotherapy; b) means of achieving and monitoring compliance; c) the extent to which nondietary intervention control patients modify their own fat consumption; d) the degree of fluctuations in fat intake in both the intervention group and controls, and the reasons for those fluctuations; and e) possible interaction between cytotoxic drugs and low-fat diet with regard to toxic side-effects. The second, long-term, objective is to utilize the experience gained from the feasibility study to participate in the design and execution of a multi-center phase III clinical trial of the low-fat diet as additional adjuvant therapy in Stage II breast cancer patients receiving combination chemotherapy. Eligible patients would be postmenopausal, and of known estrogen and progesterone receptor status.